The Medical Image Perception Conference XI will bring together people investigating the process of extracting diagnostic information from medical images. This includes radiologists, psychologists, statisticians, physicists, engineers, and others in this growing research community. The goal of the MIPS conference is to exchange current research, hold tutorial overviews, and to have workshops on current challenging or "hot topic" issues. The main strengths of this conference are its continued growth in attendance, its retreat workshop setting, and its traditional gathering of new students and key researchers on the problem of extracting diagnostic information from medical images by human and machine readers. MIPS XI will be our first international meeting and thus represents a new stage in the growth of the society and the conference. The conference will be organized jointly by the University Derby, Derby United Kingdom, St. Martin's College, Lancaster United Kingdom and the Medical Image Perception Society. The conference will run from September 27 through September 30, 2005 at the Old England Hotel, Bowness on Windermere located on the shores of Lake Windermere, England. Nine topic areas have been selected for the conference, each reflecting an important dimension of the radiological image interpretation process, that are especially relevant for the digital reading environment: (1) Detection & discrimination of abnormalities; (2) Cognitive & psychophysical processes; (3) Perception errors; (4) Search patterns; 5) Human & ideal observer models; (6) Computer-based perception: CAD & CADx; (7) Impact of display & ergonomic factors on image perception & performance; (8) Role of image processing on image perception & performance; and (9) Assessment methodologies (e.g., advances in ROC methods). One of our main reasons for having MIPS XI in a more international setting is to expose the North American attendees to research programs and studies that generally do not make it over to US conferences or get published in US journals.